1. Field of the Invention
This invention relates, in general, to improvements in shielded multiconductor, flat circuitry and, more particularly, to means for and methods of terminating, especially mass terminating, the circuitry while maintaining electrical continuity in the shielding.
2. Description of the Prior Art
Multiconductor, flat, flexible cables, hereinafter also referred to as flat cables, have come into extensive use. They generally include a ribbon or tape of an insulating material enclosing a plurality of round or thin flat conductors disposed in parallel spaced-apart relationship. In some applications, flat cables must be electrically shielded to prevent cross talk. Such electrical shielding may be encapsulated with the insulation of the cable, as in U.S. Pat. Nos. 3,576,723 and 3,612,743, or deposited on an exterior surface of the insulation, as in U.S. Pat. No. 3,469,016.
Such cables, with or without shielding, have been terminated by various means, such as the insulation displacement connector exemplified by U.S. Pat. No. 3,444,506. Such termination presents no problems when the cable is unshielded.
In some applications, however, it is desirable to mass terminate the shielded cable. In these applications, the presence of the shield impedes mass termination, since the connectors cannot be terminated directly to the cable because the shield would short-circuit the conductors. Therefore, the shield has to be separate from the conductors, and the conductors and shield have to be terminated separately. Various methods have been used in the past to accomplish this; one method was to first to cut away the shield from that portion of the cable where the conductors were to be terminated, to prevent short circuiting of the shield to the conductors. However, this method was undesirable because the electrical shield was no longer electrically terminated to the connector and there were electrical discontinuities in the shield. Another method, as noted in the above-mentioned patents, was to place a drain wire in continuous contact with the shield along the length of the cable. This overcame the problem of terminating the shield to the connector. However, the obstacle of having to remove the shield still remained. Several other difficulties arose therefrom, including having to jacket the cables and to precisely space the drain conductor from the core cable conductors. Using this method, mass termination was still cumbersome, since the insulation jacket had to be stripped to reach the shield, and the shield had to be cut away to reach the drain wire. Also, during these operations, extra care had to be used in order to maintain the spacing of the drain wire from the conductors.